Preheat oven to 350 degrees F. Grease and flour a 9-inch round cake pan.
In a medium bowl, whisk together the flour, cocoa powder, baking powder, baking soda and salt. Set aside.
In a large bowl using a hand mixer or stand mixer with the paddle attachment, beat together the sugar and oil until combined.
Add the eggs one at a time, beating after each addition until fully incorporated.
Beat in the vanilla extract.
Add half of the dry ingredients to the wet ingredients and mix until combined. Add in the buttermilk and mix until combined. Add in remaining dry ingredients and mix until just combined.
Pour batter into prepared pan and bake for 30-35 minutes or until a toothpick inserted into center comes out clean.
Cool cake completely before frosting with Chocolate Ganache (see recipe below).